NOTE:
• As a cause for many problems, there is a possibility that abnormal learning of the common rail system has occurred. Before starting the diagnosis, perform learning of the fuel pump and fuel injector. 
• Malfunction of parts other than those listed is also possible.
• Even if the malfunction indicator light is not lit, read DTCs with the Subaru Select Monitor or general scan tool, and if a DTC appears, perform diagnosis according to the relevant DTC.
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Symptoms |
Problem parts |
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1. Engine stalls during idling |
1) Electronic throttle control |
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2) Mass air flow and intake air temperature sensor | |
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3) Engine coolant temperature sensor (*1) | |
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4) Crankshaft position sensor (*2) | |
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5) Camshaft position sensor (*2) | |
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6) Glow plug and glow relay (*1) | |
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7) EGR control valve | |
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8) Catalytic converter & DPF | |
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9) Sub fuel pump | |
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10) Common rail pressure sensor | |
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11) Fuel injector (*3) | |
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12) Fuel pump (*5) | |
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13) Fuel injector wiring | |
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14) Suction control valve (*5) | |
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2. Rough idling |
1) Electronic throttle control |
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2) Mass air flow and intake air temperature sensor | |
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3) Engine coolant temperature sensor (*1) | |
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4) Air intake system (*4) | |
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5) Crankshaft position sensor (*2) | |
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6) Camshaft position sensor (*2) | |
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7) Glow plug and glow relay (*1) | |
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8) EGR control valve | |
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9) Catalytic converter & DPF | |
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10) Sub fuel pump | |
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11) Common rail pressure sensor | |
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12) Fuel injector (*3) | |
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13) Fuel pump (*5) | |
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14) Suction control valve (*5) | |
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3. Engine does not return to idle. |
1) Engine coolant temperature sensor |
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2) Accelerator pedal position sensor | |
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3) Common rail pressure sensor | |
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4) Fuel injector (*3) | |
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5) Fuel pump (*5) | |
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6) Suction control valve (*5) | |
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4. Poor acceleration |
1) Mass air flow and intake air temperature sensor |
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2) Electronic throttle control | |
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3) Engine coolant temperature sensor (*1) | |
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4) Crankshaft position sensor (*2) | |
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5) Camshaft position sensor (*2) | |
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6) A/C switch and A/C relay | |
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7) EGR control valve | |
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8) Catalytic converter & DPF | |
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9) Common rail pressure sensor | |
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10) Pressure limiter | |
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11) Turbocharger | |
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12) Accelerator pedal position sensor | |
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13) Glow plug and glow relay (*1) | |
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14) Manifold absolute pressure and intake air temperature sensor | |
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15) Fuel temperature sensor | |
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16) Fuel injector (*3) | |
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17) Fuel pump (*5) | |
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18) Suction control valve (*5) | |
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5. Engine stalls, hesitates, or sputters at acceleration. |
1) Mass air flow and intake air temperature sensor |
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2) Engine coolant temperature sensor (*1) | |
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3) Crankshaft position sensor (*2) | |
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4) Camshaft position sensor (*2) | |
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5) EGR control valve | |
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6) Common rail pressure sensor | |
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7) Electronic throttle control | |
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8) Manifold absolute pressure and intake air temperature sensor | |
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9) Fuel injector (*3) | |
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10) Fuel pump (*5) | |
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11) Suction control valve (*5) | |
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6. Surging |
1) Mass air flow and intake air temperature sensor |
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2) Engine coolant temperature sensor (*1) | |
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3) Crankshaft position sensor (*2) | |
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4) Camshaft position sensor (*2) | |
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5) EGR control valve | |
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6) Accelerator pedal position sensor | |
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7) Common rail pressure sensor | |
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8) Turbocharger | |
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9) Fuel injector (*3) | |
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10) Fuel pump (*5) | |
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11) Suction control valve (*5) | |
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7. After-burning in exhaust system |
1) Mass air flow and intake air temperature sensor |
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2) Engine coolant temperature sensor (*1) | |
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3) Crankshaft position sensor (*2) | |
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4) Camshaft position sensor (*2) | |
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5) Fuel injector (*3) | |
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6) Fuel pump (*5) | |
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7) Suction control valve (*5) | |
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8. Black smoke emitted |
1) Crankshaft position sensor (*2) |
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2) Camshaft position sensor (*2) | |
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3) EGR control valve | |
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4) Mass air flow and intake air temperature sensor | |
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5) Air intake system (*4) | |
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6) Engine coolant temperature sensor (*1) | |
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7) Manifold absolute pressure and intake air temperature sensor | |
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8) Common rail pressure sensor | |
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9) Fuel temperature sensor | |
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10) Fuel injector (*3) | |
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11) Fuel pump (*5) | |
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12) Turbocharger | |
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13) Catalytic converter & DPF | |
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14) Suction control valve (*5) | |
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9. White smoke emitted (At starting and when engine is cold) |
1) Crankshaft position sensor (*2) |
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2) Camshaft position sensor (*2) | |
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3) Glow plug and glow relay (*1) | |
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4) Mass air flow and intake air temperature sensor | |
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5) Air intake system (*4) | |
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6) Engine coolant temperature sensor (*1) | |
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7) Manifold absolute pressure and intake air temperature sensor | |
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8) Common rail pressure sensor | |
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9) Fuel temperature sensor | |
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10) Fuel injector (*3) | |
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11) Fuel pump (*5) | |
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12) Turbocharger | |
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13) Catalytic converter & DPF | |
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14) Suction control valve (*5) | |
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10. Engine noise |
1) Crankshaft position sensor (*2) |
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2) Camshaft position sensor (*2) | |
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3) EGR control valve | |
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4) Mass air flow and intake air temperature sensor | |
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5) Engine coolant temperature sensor (*1) | |
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6) Manifold absolute pressure and intake air temperature sensor | |
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7) Common rail pressure sensor | |
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8) Fuel temperature sensor | |
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9) Fuel injector (*3) | |
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10) Fuel pump (*5) | |
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11) Turbocharger | |
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12) Glow plug and glow relay (*1) | |
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13) Suction control valve (*5) | |
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11. Excessive fuel consumption |
1) Crankshaft position sensor (*2) |
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2) Camshaft position sensor (*2) | |
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3) EGR control valve | |
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4) Mass air flow and intake air temperature sensor | |
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5) Air intake system (*4) | |
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6) Engine coolant temperature sensor (*1) | |
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7) Manifold absolute pressure and intake air temperature sensor | |
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8) Common rail pressure sensor | |
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9) Fuel temperature sensor | |
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10) Fuel injector (*3) | |
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11) Fuel pump (*5) | |
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12) Turbocharger | |
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13) Catalytic converter & DPF | |
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14) A/C switch and A/C relay | |
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15) Generator | |
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16) Suction control valve (*5) | |
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17) DPF pressure difference sensor (*6) | |
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12. Cranking time too long |
1) Crankshaft position sensor (*2) |
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2) Camshaft position sensor (*2) | |
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3) Mass air flow and intake air temperature sensor | |
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4) Engine coolant temperature sensor (*1) | |
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5) Common rail pressure sensor | |
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6) Fuel temperature sensor | |
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7) Fuel injector (*3) | |
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8) Fuel pump (*5) | |
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9) Glow plug and glow relay (*1) | |
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10) Catalytic converter & DPF | |
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11) Suction control valve (*5) |
*1: Symptom occurs only when outside temperature is low.
*2: Ensure that the part is installed securely.
*3: Replace this part only when there are no malfunction in the related parts and the malfunction is found in the part in question.
*4: Inspect for air leak in air intake system.
*5: Replace this part only when there is no fault in the related parts and when fault is found in the part in question as a result of diagnosis using “Diagnostic Procedure without Diagnostic Trouble Code (DTC)”.
*6: Check the DPF pressure difference sensor pipe for disconnection, wrong connection, and damage.